class Solution {
public:
    bool check[16][16];
    int m, n;
    int sum = 0;
    int getMaximumGold(vector<vector<int>>& grid) {
        m = grid.size(), n = grid[0].size();
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (grid[i][j] != 0) {
                    check[i][j] = true;
                    dfs(grid, i, j, grid[i][j]);
                    check[i][j] = false;
                }
            }
        }
        return sum;
    }
    int dx[4] = {0, 0, -1, 1};
    int dy[4] = {-1, 1, 0, 0};
    void dfs(vector<vector<int>>& grid, int i, int j, int path) {
        sum = max(sum, path);
        for (int k = 0; k < 4; k++) {
            int x = i + dx[k], y = j + dy[k];
            if (x >= 0 && x < m && y >= 0 && y < n && !check[x][y] &&
                grid[x][y] != 0) {
                path += grid[x][y];
                check[x][y] = true;
                dfs(grid, x, y, path);
                path -= grid[x][y];
                check[x][y] = false;
            }
        }
    }
};